Home > Protein Production & Assays > Protein Purification > Strep-Tactin®XT System > Strep-Tactin®XT - Purification Buffers

Buffers & Reagents for Protein Purification with Strep-Tactin®XT

Product Contents Cat.no Price   Order
Avidin 15 mg 2-0204-015 USD 111.00  
2-0204-015

Avidin prevents biotinylated proteins from binding to Strep-Tactin® or Strep-Tactin XT columns during Twin-Strep-tag and Strep-tag® protein purification.

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Avidin 50 mg 2-0204-050 USD 218.00  
2-0204-050

Avidin prevents biotinylated proteins from binding to Strep-Tactin® or Strep-Tactin XT columns during Twin-Strep-tag and Strep-tag® protein purification.

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Anhydrotetracycline 50 mg 2-0401-001 USD 159.00  
2-0401-001

Anhydrotetracycline for induction of tet promoter controlled pASK-IBA and pASG-IBA vectors. ...

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Anhydrotetracycline 25 mg 2-0401-002 USD 87.00  
2-0401-002

Anhydrotetracycline for induction of tet promoter controlled pASK-IBA and pASG-IBA vectors. ...

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Biotin Blocking Buffer 2 ml 2-0501-002 USD 78.00  
2-0501-002

Biotin Blocking Buffer is recommended for blocking biotinylated proteins on Western blots prior to detection of Strep-tag® proteins with the Strep-Tactin® AP conjugate or Strep-Tactin® HRP conjugate.

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10x Buffer W; Strep-Tactin®/Strep-Tactin®XT Wash Buffer 100 ml 2-1003-100 USD 43.00  
2-1003-100

Strep-Tactin®/Strep-Tactin®XT Wash Buffer is used for the removal of unbound molecules from immobilized Strep-Tactin® and Strep-Tactin®XT during Strep-tag® protein purification.

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Biotin 2 g 2-1016-002 USD 74.00  
2-1016-002

Biotin is a water-soluble B-complex vitamin (vitamin B7 or vitamin H) ...

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Biotin 5 g 2-1016-005 USD 159.00
2-1016-005

Biotin is a water-soluble B-complex vitamin (vitamin B7 or vitamin H) ...

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Strep-tag® II peptide 1.8 mg 2-1018-002 USD 85.00
2-1018-002

Synthetic Strep-tag® II peptide for competitive elution of Strep-tag® II proteins from StrepMAB-Classic columns.

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10x Buffer BXT; Strep-Tactin®XT Elution Buffer 25 ml 2-1042-025 USD 62.00  

*** This article replaces 2-1041-250, 1x Buffer BXT *** ...

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Explanation:

Buffer W: Strep-Tactin®/Strep-Tactin®XT Wash Buffer

For removal of unbound proteins and other material during Strep-tag® protein purification via Strep-Tactin® and Strep-Tactin®XT columns.

Buffer BXT: Strep-Tactin®XT Elution Buffer with Biotin
Biotin displaces Strep-tag®II and Twin-Strep-tag® fusion proteins at the biotin-binding site of Strep-Tactin®XT in a competitive manner resulting in a mild elution of the protein. For your convenience, we offer biotin ready-to-use in solution (Buffer BXT with 50 mM BIotin). If you wish to prepare your own elution buffer, biotin is also offered as a lyophilized powder. Please note that after elution with Buffer BXT, the Strep-Tactin®XT column can be regenerated for atleast 3-5 times with freshly prepared NaOH (10-50 mM).

Do not use in combination with Strep-Tactin®!!!

Buffer R: For activity check of Strep-Tactin®XT

Contains HABA (2-[4'-hydroxy-benzeneazo]benzoic acid), which binds to the biotin-binding site of Strep-Tactin®XT. The yellow HABA solution turns orange after binding to Strep-Tactin®XT, clearly indicating the activity status of the column.

Do not use for regeneration of Strep-Tactin®XT!!!

BioLock - Biotin Blocking Solution

Biotin is often present in cell culture media. Its nearly irreversible binding to Strep-Tactin® has to be taken into account when recombinant proteins, secreted to the cell culture supernatant, are aimed to be directly purified via Strep-Tactin® affinity chromatography for two reasons:

  • It efficiently competes with the (Twin-)Strep-tag® target protein, thereby preventing it from binding to the resin
  • it inactivates Strep-Tactin® resins and thus, makes re-use impossible.


BioLock is a ready-to-use and cost effective solution for the removal of free biotin from cell culture supernatant. It simply has to be added to the cell culture supernatant prior to purification.

The required amount of BioLock for effective biotin blocking can easily be determined since 1ml BioLock blocks 70 μg biotin. In addition we provide a table with the required BioLock amounts for standard mammalian and insect cell culture media at
www.iba-lifesciences.com/technical-support.html >> troubleshooting>> Biotin Blocking

Anhydrotetracycline

Is used for induction of tet promoter controlled pASK- and pASG-IBA vectors. The E. coli expression cassette of the Strep-tag®/Strep-Tactin® overexpression system is under transcriptional control of the tetA promoter/operator and repressor. The promoter is induced by a low concentration of anhydrotetracycline (AHT) saving costs and minimizing the antibacterial influence of AHT.

Avidin

Prevents biotin and biotinylated proteins from binding to Strep-Tactin® columns during Strep-tag® protein purification. This is important if growth media containing free Biotin are used (for further information see “Biotin Blocking”).

Biotin
Biotin should only be used for elution of Strep-tag®II/Twin-Strep-tag® fusion proteins in certain applications. It is recommended for elution from Strep-Tactin® spin columns and Strep-Tactin®XT because of the higher affinity to Strep-Tactin® allowing a more efficient elution (compared to Desthiobiotin) of (Twin-)Strep-tag® fusion proteins. For protein complex and PPI applications, Biotin is also recommended for elution since the Strep-Tactin® resins should not be regenerated to avoid isolation of cross contaminations.
Please do not use for elution from Strep-Tactin® resin!!!

Biotin Blocking Buffer (Western blots)

For blocking biotinylated proteins in Western blots (like BCCP protein from E. coli, see Applications), the membrane is incubated with Biotin Blocking Buffer. Use a dilution of 1:1000 in standard Western blot blocking reagent prior to detecting Strep-tag® proteins with Strep-Tactin® conjugates.

Strep-tag®II Peptide

For specific customer purposes.